This invention relates to a bond seam coating composition of a polyamide resin, epoxide resin and an amine useful in coating the bond seam between bonded FRP (fiberglass reinforced plastic) moldings, particularly in-mold coated FRP moldings or parts.
FRP (fiberglass reinforced plastics, for example, fiberglass reinforced polyesters) for automobiles and other vehicles in many cases are made in sections and bonded together by means of adhesives. This is because some of the moldings are too large to be made in one part or may be too complicated to be made in one mold. For example, the fender of one automobile is made of at least two parts. After molding, the edges to be joined are beveled to form a V-like trough or seam when brought together, a back-up FRP strip is assembled with the parts, a polyurethane or polyester adhesive is applied to the seam, and the adhesive is cured to form a bonded composite or integral article, molding, fender and so forth. The seam area is then sanded, primed, sealed and painted. Even after such treatment, it is many times possible to see the seam line. These parts also, may show paint pops, sinks and so forth. Sanding and repainting or finishing are required to obtain the proper Class "A" surface. While many of these problems have been overcome by use of the in-mold coating process, it has been found that the adhesives used to bond the parts together still give bonded parts which exhibit a seam on examination at an angle in ordinary light and paint pops, sinks and so forth in the seam area. The seam is particularly noticeable since the in-mold coating process gives FRP parts which after priming, sealing and painting exhibit a high gloss.
Accordingly, it is an object of the present invention to overcome the difficulties alluded to hereinabove and to provide bonded FRP parts which after finishing do not show paint pops, sinks and so forth and wherein the seam line is not visible or just barely visible and a process for making the same.
These and other objects and advantages of the present invention will become more apparent to those skilled in the art from the following detailed description, working example and drawing.